A large variety of munitions items, e.g., combined effects munitions (CEMs), are formed with a cavity that is filled with a specific amount of explosive material during manufacture. Until recently, one conventional technique was to melt a small amount of explosive material such as 70/30 Cyclotol or 60/40 Comp B explosive in a "kettle" and pour it into individual empty munitions items, with provision of a riser for a certain amount of the material to rise therein when the item is filled. As the poured explosive material cools within the munitions item, it experiences some shrinkage and draws in some of the still molten material from the riser. Eventually the riser material is knocked off and the excess explosive material therein is collected for reuse or disposal. This known technique is wasteful, slow and somewhat dangerous. The amount of riser material that is scrapped with each munitions item filled often is a high percentage of the material initially melted. Naturally, this represents an energy waste and carries with it an inherent danger of accidents as the scrap has to be collected manually and recycled or reprocessed. Also, because the method requires much personal handling by relatively skilled operators it is both slow and expensive. This is especially true when large numbers of similar munitions items are to be filled.
Initial experiments aimed at developing apparatus and methods for injection loading of molten explosive into individual munitions items employed a vertical downward dispensation of a controlled volume of molten explosive into the empty item held upright, somewhat similar to the action of a vertically held hypodermic syringe used by a doctor to inject a fluid into a body part. Particulate HMX in the molten explosive material mixture had a tendency to settle out in front of the discharge valve in this apparatus and caused intermittent clogging of the valve. Thus, while this solution is capable of reducing riser scrap to approximately 10% (compared to as much as 300% by older methods) with explosives such as 70/30 Cyclotol or 60/40 Comp B, it is unsuitable for use with a viscous explosive like Octol which is normally mixed with the particulate component HMX. The problem is aggravated when large numbers of similar munitions items are to be filled.
Further research and development led to the development of the apparatus and method of the present invention, which provides a user the facility to inject a controlled amount of virtually any meltable explosive, including mixtures containing particulates, simultaneously into pluralities of munitions items consistently, quickly, with the production of only a minimal amount of riser scrap, and to a higher loading density than the acceptable minimum.